Devices for making photographic copies



June 4, 1963 w. LIMBERGER DEVICES FOR MAKING PHOTOGRAPHIC COPIES June 4,1963 w. LIMBERGER 3,092,006

' DEVICES FOR MAKING PHOTOGRAPHIC COPIES Filed Feb. 5, 1960 3 Sheets-Sheet 2 June 4, 1963 w. LIMBERGER 3,092,006

DEVICES FOR MAKING PHOTOGRAPHIC COPIES Filed Feb. 5, 1960 3 Sheets-Sheet a United States Patent 3,092,006 DEVICES FOR MAKING PHOTOGRAPHICCOPIES Walter Limberger, Hamburg, Germany, assignor to Lumoprint Zindler K.G., Hamburg, Germany Filed Feb. 5, 1960, Ser. No. 7,012 Claims priority, application Germany Feb. 24, 1959 6 Claims. (Cl. 95-775) The invention relates to devices for making photographic copies of that type in which a positive and a negative layer carrier are passed through a developing station simultaneously, but separated at least in certain zones thereof.

Devices of this type are known. They use diffusion developing in a bath, the positive and the negative layer carrier being passed through the bath and guided to a pair of squeezing rollers which, at the same time, serve to transport the layer carriers out of the apparatus. Devices of this type require relatively numerous transport means, as on the one hand the original and the negative layer carrier and on the other hand the positive layer carrier are guided over separate paths, and pairs of transport rolls for each path are arranged particularly in front of the feeding channels to the bath container.

Due to this a relatively large driving capacity is required, and besides this difiiculties arise in production as an exact, synchronous motion must be obtained, in order to safeguard that the layer carriers are matingly moved one upon the other.

Furthermore the known devices comprising a bath container for the diffusion development are disadvantageous in that the developing liquid will be spent rather quickly by the influence of oxidation, and usually the container must be lifted out of the device for changing the developing liquid. This is a rather awkward job so that often the changing of the developing liquid is delayed and the copies will be of inferior quality. It has also been proposed to provide a supply container for the developing liquid. However, these supply containers have a relatively small capacity and, besides this, are often movably arranged so that the construction is complicated and the costs for the apparatus are raised.

Devices of this type which are combined with exposure means often use an exposure device comprising a translucent cylinder within which a light source is arranged and around which the original and the negative paper are passed for example by means of rubber belts. The rubber belts are passed over at least three rolls spaced around the cylinder. Another drawback of the known devices is to be seen in that the discharged original often falls down at the operating side of the device and is obstructive.

Funthermore, the devices of this type have the disadvantage that the originals and negative layer carriers are usually kept separate of the device resulting in a considerable loss of time when using the device, as these papers must be taken out of packages and be placed matingly one upon the other.

The main object of this invention is to provide an improved device of the aforementioned type in which the above mentioned disadvantages are avoided and in which a guide element separating the layer carriers in at least part of the developing station between pairs of drive rollers associated with the layer carriers and, if occasion arises, with the original, the guide element being provided with one or more apertures adjacent the drive rollers, the rollers extending through the apertures contacting each other in cooperating relation to engage the layer carriers upon feeding them into the device.

Due to this arrangement numerous drive rolls are dispensable which hitherto were deemed necessary, and at 'ice the same time an absolutely synchronous motion of advance is obtained.

Another object of the invention is to provide a copying device of the aforementioned type in which the aperture or apertures provided in said guide element are narrower than the width of the layer carriers the edges of which will therefore always be separated from each other.

Another object of the invention is to provide an aperture in said guide element the edge of which lies in the direction of advance of the layer carriers and is formed by a gradual convergence of the side edges of the aperture.

Another object of the invention is to provide a copying device comprising an exposure device formed by a cylinder having a source of light arranged therein, said cylinder being supported within one or more belts pressingly engaging said cylinder, said belts being guided for example over three rollers a guide element for the layer carriers extending along one side of the exposure device, the guide rollers or belt being arranged on one side of the guide element and directly cooperating with the transport rollers provided on the other side of the guide ele ment.

Another object of the invention is to provide a copying device in which the transport rollers are resiliently supported and elastically and yieldingly pressed against the guide rollers.

Another object of the invention is to provide a copying device provided with a flat bath container the upper defining wall of which being formed by the bottom side of a supply container.

Another object of the invention is to provide a supply container comprising a closable outlet stud directed into the bath container and a pipe extending into the sump of said bath container, the inner space of said supply container being in communication with a pump, preferably a plunger pump.

Another object of the invention is to provide a pump having a cylinder volume equal to the required filling of the bath container.

Another object of the invention is to provide closure means in the duct connecting the supply container with the pump, for example a cock.

Another object of the invention is to provide a separately closable outlet each for the supply container and the bath container, the outlet of the supply container being arranged so as to determine the height of the liquid level in the bath container.

Another object of the invention is to provide a supply container the bottom of which is spaced parallel to the shape of the guide element or the bottom of the bath container respectively, said supply container extending over adjacent parts of the device within the housing.

Another object of the invention is to provide a copying device comprising a desklike housing having a common feed opening for the original and the negative layer carrier, in which the original is outwardly returned through the feed opening, and an arrangement of stack holding means adapted to receive the originals and the negative layer carriers, said stack holding means being arranged directly on the housing of the device.

Another object of the invention is to provide stack holding means which are arranged in a superposed and staggered fashion, the outlet ends of which extending over the slanting surface of the desk-like front side of the housing.

Another object of the invention is to provide stack holding means which are detachably arranged on the housing.

Another object of the invention is to provide a copying device in which the stack of positive layer carriers is arranged on a stack holder located below the feed opening,

r 3 the stack holder being resiliently urged against an advance roller with at least one end.

Another object of the invention is to provide a stack holder for the positive layer carrier which is urged against an abutment surface located below an advance roll, said stack holder being arranged in such a way that the border zone of the layer carriers located opposite the advance roller may be grasped at the front side of the device.

Another object of the invention is to provide a copying device having a platform or table for depositing the original arranged above the stack of positive layer carriers and below the exposure device, said table being accessible through the feeding opening, wherein the exposure device and the separating means for the original and the negative layer carriers are dimensioned and arranged in such a Way that the original will be deposited on the table with its leading edge located within the feeding opening or extending out of it.

Another object of the invention is to provide a copying device in which the advance roller also projects into the guide path in which the original is turned back to the table.

In the following the invention shall be described in connection with the attached drawings in which several embodiments of the invention are shown by way of example only, and it is to be understood that the invention shall by no means be limited to the examples shown and to be described, as changes are possible without departing from the scope of the invention.

Referring to the drawings:

FIG. 1 is a sectional side view of the device showing the features of the invention,

FIG. 2 is a schematic top view of a detail of FIG. 1,

FIG. 3 is a sectional side view of a device in accordance with the invention being constructed differently, in which merely those parts are shown which are essential for the description of its functioning.

The device shown in FIG. 1 comprises a housing formed of a lower and an upper part substantially shaped rectangularly. Within the lower part of the housing an exposure device 2 and a developing device comprising a bath container 3 are provided, a pair of squeezing rollers being arranged within the developing device which presses the layer carriers together while they are being transported out of the outlet slot 5.

The exposure device 2 consists as usually of a rotatable cylinder 6 within which a light source 6 is arranged and around which, for example, a pressingly engaging belt 7 is passed which, for example, runs over three rolls 8, 9 and 10. At least one roll is resiliently supported in a suitable manner to tighten the belt or belts. The cylinder proper containing within its interior the light source 6' is preferably supported by the belts only.

On the face side of the housing behind which the exposure device is arranged a servicing opening 11 is provided for the original, the negative and the positive layer carrier. A guide element 12 is arranged behind the inserting slot assures on the one hand so that the layer carrier and the original upon insertion will be guided onto their path, and on the other hand that they will be guided out of the slot 11 again after they have passed the exposure device. For simplifying the operation the positive layer carrier is placed relative the exposure cylinder upon the rear side of the original and of the negative layer carrier and passed around the exposure cylinder so that, after the original and the two layer carriers are delivered out of the exposure device, merely the original has to be removed from the layer carrier arrangement, whereupon both layer carriers may be fed into the device again without necessitating that the layer carriers must be placed one upon the other anew.

The drive means for the exposure device comprising motor and gearing, are, for example, arranged within a box :13 at the side of the exposure device. It is however also possible to combine the drive of the exposure device and other driven parts, as for example thesqueezing rollers 4, in which case the drive means, including motor and gearing, may be arranged as at 14. At least one, preferably however both of the squeezing rollers 4 are driven. One of the rolls is urged resiliently against the other roll by a spring 15. The drive is derived from shafts which extend with their drive ends out of one or both boxes 13, 14, being unvisible in the drawing, as they are covered by the driven parts. Clutches and for example helical endless springs may be provided. The rotating and/ or driven parts are provided with arrows indicating the direction of rotation. Another inserting slot 15 for the exposed negative layer carrier and the positive layer carrier is provided above the inserting slot 11 in front of the exposure device. Behind the inserting slot 15 the end of a guide element 16 is arranged extending, according to the embodiment shown as example, through the bath container 3 by means of which a separate guidance of the layer carriers is obtained in the bath. The part of the guide element extending through the bath is provided with perforations.

The end of the guide element 16 is located in the middle of the inserting slot 15 or at least sufficiently spaced from its lower edge, as one layer carrier is inserted above the guide element and the other layer carrier below'the guide element.

The guide element is provided with an aperture 19. Within the range of this aperture the belt 7 pressingly engages the exposure cylinder 6 and is arranged directly adjacent the guide element 16, or respectively in the plane of the guide element so that the belt 7 will cooperate with counter rollers 17 and 18' which are arranged within the range of the aperture 19. The counter rollers 17, 18 are thus rotated by contacting the belt directly, or in another form of embodiment in which several belts are arranged side by side, for example, also on the circumference of the rollers 9 and 10. It is to :be noted that a separate drive of the counter rollers 17, 18 is not required. The rollers are suitably supported in the housing and are freely and rotatably mounted therein and are rotated by the friction, for instance of the pressingly engaging belt, or the interposed layer carriers. Advantageously the counter rollers 17, 18 are resiliently urged against the rollers 9, 10, or against the surface of the belt 7 which is guided over these rollers.

As may be seen in FIG. 2 the aperture 19 is narrower than a layer carrier 20 by means of which the guidance of the layer carrier above and below the guide element 16 is maintained, even if both layer carriers are moving in contacting relation between roller arrangements 9, 18 or '10, 17. The end of the aperture 19 lying in the direction of advance is closed by a slowly converging and reduced width portion of the aperture and the middle zone of the advancing edge of the layer carrier is slowly lifted onto the following closed surface of the guide element 16 without being bent or bulged.

This arrangement secures a separate guidance of the two layer carriers by using one pair of rollers each, the illustrated arrangement being especially advantageous besides, as always one roller of the pairs of rollers is formed by the drive rollers of the exposure device.

According to an advantageous form of one embodiment the guide element consists of a piece of perforated sheet metal of stainless steel.

A guiding surface 21 arranged 'between the rollers 17 and .18 cooperates with the guide element 16. Below the belt 7 and between the rollers 9, 10 of the exposure device a blind screen 22 is arranged by means ofwhich rays from the exposure device are avoided which might influence the layer carriers transported along the guide element 16 by light or heat.

According to a preferred form of an embodiment of the invention the bath container 3 comprises a guiding element 2% formed in accordance with the guide path and being arranged in a support 23, said guide element extending to the bite of the pair of squeezing rollers 4. The bath container is upwardly covered by the bottom 25 of the supply container 26 so that only a relatively narrow space is formed within the range of the liquid level in the middle of which it is secured, so that the layer carriers will he guided separately and will be well moistened.

As may be seen the bath container is constructed rather shallow. On the lower side of the bath container 26 preferably ribs 70 are formed and are adapted to guide the layer carriers through the guide path of the bath container. Corresponding ribs 71 are arranged on the bottom of the bath container. Special ribs of greater height which, for example, are arranged on the edge of the bath container adjacent the guide path for the layer carriers serve to introduce the guide element 16 into the middle of the bath container.

The holding capacity of the supply container is many times as much as the required amount for the bath. It is pointed out, for example, that according to one embodiment the ratio between the holding capacity of the bath container to that of the supply container is 1:20. In this case the supply container holds approximately 3 liters. This ratio can be obtained in an embodiment according to FIG. 1. Due to this a very long operating period is possible once the apparatus has been filled with developing liquid, particularly so, as the developing liquid of the bath is mixed with the liquid of the supply container in a manner that will be hereinafter more fully described. The bath container also extends into zones of the device positioned sidewards of the bath container 3, and particularly, for example, over the exposure device 2. The bottom of the supply container is adapated to the shape of the guide element 24. Furthermore the supply container is provided with an opening through which it may be filled and which may be closed by a cover screw 27 in an air-tight manner.

In additon the supply container communicates with the bath container via an outlet 28 which is arranged at such a height that it will determine the liquid level of the bath container. The outlet is provided with closing means consisting of a lever system 29, 3t), 31 from the operating side of the device, so that the outlet may be closed at will.

Furthermore a sump 32 is formed in the bottom of the bath container into which a pipe 33 projects and is connected with the supply container.

Evidently, if the outlet 28 is open the bath container will only be filled to a height determined by the position of the outlet, as the supply container is constructed in an air-tight manner with the exception of the outlet, and this opening through the pipe 33 will also be sealed by the liquid.

A pump 35, for example a plunger pump is connected via an air-tight duct 34 leading into the cover of the supply container. This pump is so constructed and arranged that the connection is air-tight. It'is, however, possible to provide a closing element, for example a cock, in the duct 34 between the supply container and the pump, by means of which an air tight closure may be obtained with reasonable certainty.

The plunger pump comprises a cylinder within which a piston is reciprocably mounted. The piston is connected with a piston rod extending out of the cylinder. This piston rod is provided with a handle projecting from the housing by means of which the pump may be actuated.

Preferably the pump is designed so that the amount of liquid. drawn-in .at one stroke corresponds to the contents of the bath container 3. For example check valves are arranged on the plunger pump allowing the piston to be moved back into its initial position without displacing any liquid. If the outlet 28 is closed the contents of the bath container 3 may thus be returned to the supply container 26 via the duct 33 by merely actuating the pump 35 once so that the bath container is completely emptied. The bath container is sealed automatically by a residue of liquid remaining in the sump 32 and sealing the lower opening of the duct 33.

If the device is to beused it is merely necessary to open the outlet 28 by the lever system 29-31 and the bath container will be filled up to a height determined by the position of the outlet 28.

According to another form of embodiment the supply container is merely provided with an outlet directed into the bath container the height of which determines the liquid level of the bath container in a manner like a chicken water trough. This outlet is closable. The bath container is provided with a closable outlet which, for example, is connected with the sump 32 to allow the bath container to be emptied. According to this embodiment the liquid of the bath is not pumped back into the supply container.

Furthermore, it is to be noted that the upper side of the housing 1 is covered with a special top 36 which on the one hand covers the filling opening closed by the cap screw 27 and on the other hand also encases the duct 34 so that a closed upper side of the device is obtained.

In FIG. 2 the construction of the guide element 16 is shown schematically. In FIG. 2 it may be noted that, for example, either two advance rollers 37, 38 may rotatably be arranged side by side within the aperture 19 or one advance roller 39, each of which cooperating with corresponding rollers supported below the guide element 16.

Following the device shown in FIG. 3 shall be referred to. This device shows an especially advantageous total arrangement, as no extra insertion of the positive layer carrier is necessary, and the original is automatically partly deposited on a table 43 arranged for this purpose within the housing of the device.

Within the housing of the device, at the insertion end an exposure device 40 is provided the construction of which essentially corresponds to the exposure device 2 shown in FIG. 1. Behind the exposure device a guide element 41 is .adjoiningly arranged which will guide the original and the negative layer carrier coming out of the exposure device to a pair of separating rollers 42, known per se. The negative layer carrier is adapted to pass through the gap between the rollers which are rotated in a direction shown by the arrows, while the original is lifted off and brought into guide path 53 ending on the table 43 beneath the exposure device 40, the guide path 53 is defined by the guide surface 76 and 77. The exposure device 40 is dimensioned, and with respect to the pair of separating rollers arranged in such a way that the original will automatically be pushed over the table 43 into the feeding slot 44 of the device, so that the original may readily be removed. It is to be noted, that according to the advantageous embodiment a considerable space has been provided between the table 43 and the exposure device, so that, if occasion should arise, also several originals may be stored on the table 43 before they are removed.

A special embodiment also includes the possibility to ,utilize the returning section of the belt or belts 47 which yieldingly engage the exposure device to transport the original out of the device. In this embodiment the table 43 is arranged below the belt or belts a distance being a little greater than'the thickness of the original. In this it should be considered that the original will then be transported out of the device over the table 43 by the friction of the belt or belts.

The original and the negative layer carrier areinserted over an especial guide surface 45 and fed between the advancing section of the belt or belts 47 passed around the cylinder of the exposure device and an advance roller 46. Therefore, the original and the negative layer carrier will move on these belts 47 to the exposure cylinder. It is to be noted that the advance roller 46 cooperates with a guide roller 48 for the belts 47. Correspondingly another advance roller 49 is associated with the guide roller 74.

Below the servicing opening 44 and the table 43 a stack 50 of positive layer carriers are arranged. The

stack is deposited on a stack holder which is supported on a spring 51 at least at its inner end so that the top layer carrier is urged against the advance roller 52 according to one embodiment of the device. At the same time this advance roller may suitably project into the guide path 53 and aid in advancing the originals on the table 43.

For this purpose the advance roller 52 may be provided with radially and outwardlyextending side flanges projecting into corresponding apertures provided at the rear end of the table which forms a guide element with its upwardly curved end portion.

Due to the illustrated arrangement of the positive layer carriers the top layer carrier is always pushed into a channel 54 until it is stopped by an abutment 55 at the end of this channel. The abutment proper is arranged on a pivotal lever 56 being pivotally connected with the edge of a guide element directed to the middle of the device, said guide element 57 corresponding to the guide element 16 of FIG. 1. Above the guide element 57 is the end opening of a channel 58 defined by two guide surfaces and through which thenegative layer carrier, passes and advances through the gap between the separating rollers 42. At the end of the channel 58 the negative layer carrier engages the pivotal lever 56 and thus urges the abutment 55 out of the channel 54. It should be noted that the channel 54 ends at the lower side of the guide element 57. The channel 54 is also defined by two guide surfaces.

By this means the negative layer carrier and the positive layer carrier will simultaneously arrive at the guide element on opposite sides thereof, and will advance thereon in a practically mating manner. Corresponding to the construction described in connection with FIG. 2 a pair of advance rollers 59 is associated with the guide element, the rollers being arranged within an aperture of the guide element in contacting relation, and will insure the mutual advance of the negative and positive layer carrier along the guide element 57 and through the bath container 60. At least one roller of the pair of rollers 59 is driven.

The bath container is arranged and constructed in the same way as that one shown in FIG. 1 and particularly has connection with a supply container 61. The supply container 61 merely difiers in its arrangement in space in that it is extended upwardly over the separating rollers 42 into the housing, so that a still greater proportion of liquid supply relative the bath container is obtained.

A particular description of the container with respect to its outlet opening and the arrangement of a drain pump seems to be superfluous, as the arrangement corresponds to that of FIG. 1. The controllable opening of the supply container is denominated with 78.

Behind the bath container and before the outlet slot 62 a pair of squeezing rollers 63 is arranged.

The drive elements, comprising at least a motor, driving gears and transmissions, for example in form of endless helical wire springs, which are arranged behind the sidewall 75, shown in FIG. 3, and through which the shaft of the driven parts extend. Parts which at least have to be driven are marked with arrows indicating the direction of rotation. The other rotatable parts are driven thereby.

The operation of the device is greatly facilitated by the fact,.that the insertion of the positive layer carrier does not require any special measures, as the feed is automatic.

It is to be pointed out however that also the half automatic embodiment is included, in which the stack ofpositive layer carrier in urged against an abutment surface 64 below the advance roll on which the advance roll is runningby elastically pressing againstit. -In this embodiment the stack holder projects over the front side of the device so that one edge of the positive layer carriers is accessible. Thus the top positive layer carrier can be grasped and pulled back far enough that it is free of the abutment surface. The spring 51 automatically presses the stack holder and thereby the support for the positive layer carriers against the abutment surface located thereunder so that the initially pulled back positive layer carrier is moved onto the upper side of the abutment surface 64, and thereby between the latter and the advance roll 52 when it is pushed forward again into the device. By this the positive layer carrier is moved to the abutment 55 and thus brought into a position of readiness. It is pointed out that the surface of the advance roll 52 is of a type which may have running contact with the positive layer carrier located in its position of readiness without injuring the layer.

An essential feature of the device according to FIG. 3 is to be seen in the arrangement of the stack of originals and the stack of negative layer carriers. The drawing shows, that the housing is formed desk-like with a surface 65 declining toward the front side provided with the insertion slot 44. A chamber 66 for the negative layer carrier which must be stored light-proof extends partly over the surface 65 and partly over the horizontal top wall of the housing. Above this chamber 66 another stack holder 67. for the originals is arranged. This latter stack holder may be open on top. This stack holder is particularly with respect to the chamber 66 displaced toward the back side of the device so that the end of the stack holder 67 and the chamber 66 directed towards the operating side are arranged in a staggered manner above the insertion slot 44. Therefore layer carriers may easily be removed, and it is especially preferred to provide a horizontally extending abutment ledge 68 so that each upper sheet is advancedly arranged relative the lower sheet toward the front, that means towards the outlet end.

The outlet end of the chamber 66 is closable by a cover 69 which for example may be constructed as a hinged or as a sliding cover. The position of the outlet end on the declining surface 65 will effect that the cover automatically moves into its closed position.

Suitably the originals are placed into the stack holder 67 with writing facing downwardly while the negative layer carriers are placed into the chamber 66 with their layers facing upwardly so that these sheets are stacked in such a manner as is required when inserting them into the device. In the shown and so far described arrangements it is necessary to turn back the ends of the sheets pulled out of stack holder, or the chamber respectively, upon feeding them into the inserting slot over the guide surface 45, whereby at the same time the negative layer carrier is covered by the original.

It is emphasized that it is also possible to arrange the light-proof chamber for the negative paper above the stack holder for the originals so that then the sheets are pulled out forwardly and are fed into the device without being turned back.

It is pointed out that the arrangement of the negative layer carriers and the positive layer carriers as provided is not limited to the housing having the declining surface 65, but that essential advantages reside in the arrangement of the stack holder, or the chamber respectively, directly above the housing and this preferably parallel to the housing wall and in the offset arrangement, as by means of this it is possible to locate these sheets directly at the insertion slot and readily accessible. Also a stack holder for the negative layer carrier and the original constructed as a combination with a detachable top is included in the invention.

What I claim is:

1. In a device for making copies, a receptacle for a bath of development liquid, guide means for negative and positive layer carriers extending to and through said bath along andspaced from the bottom of said bath receptacle,

a pair of driven squeeze rollers adjacent the outlet end from said bath receptacle for pressing said layer carriers against each other in pulling them out of the development bath, a development liquid supply container disposed above said bath receptacle and having its bottom part within the confines thereof and in contact with the development liquid therein to form an upper boundary for the path of said layer carriers and an upper guide surface for one of said layer carriers through the bath receptacle, connection means providing communication between said bath receptacle and supply container and having an opening that determines the liquid level in the bath receptacle, and means for interrupting said communication between the supply container and the bath receptacle said upper guide surface in contact with the development liquid, when considered in the direction of movement of the layer carriers, extending in a downwardly inclined direction at the inlet side and in an upwardly inclined direction at the outlet side.

2. A device as set forth in claim 1, in which the bottom of said supply container, the bottom of said bath receptacle, and the portion of said guide means disposed between said two bottoms have substantially corresponding curvatures.

3. A device as set forth in claim 1, in which said supply container, bath receptacle, squeeze rollers, and guide means are enclosed in a casing, the upper portion of said supply container extending sideways beyond the rim of the bath receptacle at least in one direction.

4. A device as set forth in claim 1, in which an exposure device is disposed at the inlet side of said layer carrier path, said exposure device comprising a light source, a transparent cylinder which is rotatably mounted and contains said light source, at least a first, a second, and a third guide roller journallled parallel with said cylinder and spaced around the same, at least one guide and pressure band trained about said cylinder and guide rollers, said first guide roller being disposed at the inlet to said layer carrier path while said guide means extends above said exposure device and over said first and second guide rollers and is provided with openings in the proximity of said first and second guide rollers, radially projecting flanges on said first and second guide rollers outside the edges of said guide and pressure band and extending into said openings in the guide means, first and second counter rollers associated with said first and second guide roller, respectively, and disposed at the opposite side of said guide means therefrom, enlarged sections on said counter rollers which extend into said openings in the guide means and tangentially cooperate with said first and second guide rollers, yielding bearing means for said counter rollers biasing them against said guide 10 rollers, a guide element above said guide means and spaced therefrom extending between said counter rollers, and screen means disposed between said first and second guide rollers and between said cylinder and guide means and spaced from said guide means.

5. In a device for making copies, a receptacle for a bath of development liquid, guide means for negative and positive layer carriers extending to and through said bath along and spaced from the bottom of said bath receptacle, a pair of driven squeeze rollers adjacent the outlet end from said bath receptacle for pressing said layer carriers against each other in pulling them out of the development bath, a development liquid supply container disposed above said bath receptacle and having its bottom part within the confines thereof and in contact with the development liquid therein to form an upper boundary for the path of said layer carriers and an upper guide surface for one of said layer carriers through the bath receptacle, connection means providing communication :between said bath receptacle and supply container and having an opening that determines the liquid level in the bath receptacle, means for interrupting said communication between the supply container and the bath receptacle, a pump having a piston that is reciprocable in a cylinder, means for operating said pump, conduit means extending from said pump to the upper portion of said supply container, the one-stroke volumetric capacity of said pump being substantially equal to the liquid filled volume of said ibath receptacle, conduit means extending from said supply container to the bottom of said bath receptacle, and means 'for substantially airtight closing of said supply container, whereby upon closing of the opening in said connection means operation of said pump one-stroke in the suction direction causes the development liquid in the bath receptacle to be substantially emptied into said supply container.

6. A device as set forth in claim 5, including means in said conduit means from the pump to the supply container for closing said conduit means.

References Cited in the file of this patent UNITED STATES PATENTS (Addition to No. 1,081,179) 

1. IN A DEVICE FOR MAKING COPIES, A RECEPTACLE FOR A BATH OF DEVELOPMENT LIQUID, GUIDE MEANS FOR NEGATIVE AND POSITIVE LAYER CARRIERS EXTENDING TO AND THROUGH SAID BATH ALONG AND SPACED FROM THE BOTTOM OF SAID BATH RECEPTACLE, A PAIR OF DRIVEN SQUEEZE ROLLERS ADJACENT THE OUTLET END FROM SAID BATH RECEPTACLE FOR PRESSING SAID LAYER CARRIERS AGAINST EACH OTHER IN PULLING THEM OUT OF THE DEVELOPMENT BATH, A DEVELOPMENT LIQUID SUPPLY CONTAINER DISPOSED ABOVE SAID BATH RECEPTACLE AND HAVING ITS BOTTOM PART WITHIN THE CONFINES THEREOF AND IN CONTACT WITH THE DEVELOPMENT LIQUID THEREIN TO FORM AN UPPER BOUNDARY FOR THE PATH OF SAID LAYER CARRIERS AND AN UPPER GUIDE SURFACE FOR ONE OF SAID LAYER CARRIERS THROUGH THE BATH RECEPTACLE, CONNECTION MEANS PROVIDING COMMUNICATION BETWEEN SAID 